1. Field of Invention
This invention relates in general to a health monitoring system, and in particular to the incorporation of two-way wireless communication, global location acquisition and wireless medical sensor into an intelligent health monitoring system for concurrent measuring, processing, alerting and transmission of multiple health-related vital signs of the patient wearing the system.
2. Description of Prior Art
The health monitoring system is well-understood in the art. It can be used to measure a patient's relevant vital parameters, such as blood pressure, glucose concentration, heart rate and body temperature. The measurement can be taken either continuously or at predetermined time, without the need for an in-hospital examination. The system can also be used to alert the patient and to send an emergency request to a local 911 emergency service.
Different vital sign measuring, collection and reporting methods can be used in a health monitoring system. For example, U.S. Pat. No. 6,095,985, U.S. Pat. No. 6,282,441, and U.S. Pat. No. 5,778,882, all by Raymond et al., describe a health monitoring system that collects the patient's vital signs and periodically uploads the data to a remote database where it is stored along with similar health histories for other patients. In another example, U.S. Pat. No. 6,073,046 to Patel et al. reveals a medical facility that collects the signals of a cardiovascular patient and transmits it to a remote location for analysis. Another relevant example is U.S. Pat. No. 6,171,237 to Avitall et al. that explains a remote health monitoring system that receives data from a plurality of remote test unit which is configured for a particular patient for optimal care. The health monitoring systems in the above patents are passive, data collection based systems in which the patient's vital signs are measured and transmitted to a remote location for processing and analysis. An alert, when triggered by the results of data analysis, is then sent back to the health monitoring system or to an emergency service bureau for further action. A preferable alternative to the passive, collection based system is an active, real-time monitoring based system which can measure, process, and analyze a patient's vital signs on location. Whenever an alert regarding patient's vital signs is trigged, an alarm can be activated on location to warn the patient while transmitting the information to a remote emergency service station. An example of such a situation can be pictured as a man who is lifting heavy equipment and subsequently hears a beeping sound from the health monitoring system. The beeping alerts him of an irregularity in his heart beat and warns him to stop working immediately to avoid cardiac arrest. Additional panic button can also be included in such system to be used whenever he/she feels uncomfortable about his/her health condition at anytime. Once the panic button is pressed, all vital sign data can be transmitted to a designated patient monitoring station for immediate attention.
The sensor devices of the health monitoring system are responsible for conducting vital sign measurements. The sensor devices can be located either next to the main processing unit of the health monitor system or at a position remote from patient's body where vital signs are more easily measured. For example, U.S. Pat. No. 5,479,932 to Higgins et al. describes an infant health monitoring system that includes a passive sensor connected next to a microcontroller for detection of gross motor movement, heart rate and respiration rate of the infant. When the sensor device is located at a remote position, cable wire is typically used for network connection and data transfer between the sensor device and the main processing unit. The method of attaching the sensor device next to the main processing unit as mentioned in the patent of Higgins et al. or connecting the sensor device through cable wire is inflexible if multiple sensor devices are needed for different vital sign measurements. This method will also interfere with patient's normal movement sometime. A preferable method is the use of a wireless medical sensor that not only has the capability of conducting vital sign measurement from a specific location on the patient's body but also includes the necessary apparatus to transmit data back to the main processing unit through a short-range Radio Frequency (RF) network. With a wireless medical sensor, the main processing unit of a health monitoring system can either be worn by a patient when he/she is on the move, or placed at a nearby location in the house, office, car, or wherever the short-range RF network can be reached.
The long-range data communication between the health monitoring system and the remote patient monitoring station can be conducted through either a wireline or a wireless communication network. Numerous systems have used wireline communication network as a primary mean for transmission of patient data. For example, U.S. Pat. No. 5,899,855, and U.S. Pat. No. 5,960,403, both to Brown, describe a modular self-care health monitoring system that employs a compact microprocessor-based unit for the operation of a glucose monitor, and the transmission of a signal to a remote clearing house or healthcare facility via telephone lines. Another example, U.S. Pat. No. 5,897,493 and U.S. Pat. No. 6,101,478, both to Brown, discloses a monitoring system for remote query of an individual with remote apparatus connected to a wireline telephone network. In U.S. Pat. No. 6,144,837, Quy describes an electronic health monitoring system for interactively monitoring an individual's physical condition and for providing health-related information to a television set through a television interface cable. Other systems have attempted to use a wireless communication network for conducting limited health monitoring functions. For example, in U.S. Pat. No. 6,160,478, Jacobsen et al. explain a system for remotely monitoring a patient's physical activity by including an accelerometer which is capable of measuring both the magnitude and direction of motion acceleration. The invention from Jacobsen et al, however, is limited to monitoring body acceleration and cannot measure other vital signs. Another example is U.S. Pat. No. 5,749,365 to Magill that explains a method for monitoring vital signs of a human or animal subject. The wireless device invented by Nagill is only cable of one-way data transmission and cannot provide two-way wireless communication. A desirable health monitoring system should include a long-range two-way wireless data communication module that can be used to support active, real-time vital sign monitoring of the patient. The long-range wireless data communication apparatus used in such a system shall be adopted to different cellular networks, such as Global Services for Mobile (GSM), Code Division Multiple Access (CDMA), General Packet Radio Service (GPRS) and Cellular Digital Packet Data (CDPD).
Tracking a patient's whereabouts is very important in a health monitoring system. There are two ways to determine the location of a mobile device worn by a patient: acquiring Global Position System (GPS) data by the mobile device or measuring the distance from the mobile device to nearest Base Station (BS) of the cellular network towers. GPS is a spaced-based navigation and positioning system that allows the location of a receiving system to be determined autonomously. The GPS consists of three major segments: the Space Segment, the Control Segment, and the User Segment. While the Space Segment and Control Segment are operated and administrated by the U.S. Space Command of the U.S. Air Force, the User Segment can exist either as a stand-alone commercially available receiver, or as an integration module that can be embedded into a mobile device. To accurately determine the location of a mobile device, at least three GPS satellites need to be in the line-of-sight by the mobile device. In addition to acquiring GPS data, if a mobile device is equipped with a long-range two-way wireless communication module, a mobile device's location can also be determined either by measuring the strength of a RF signal sent from the Base Stations of nearby cellular network towers, or by measuring the signal's Time-Of-Arrival (TOA) from Base Station to the mobile device. The location of the mobile device is then calculated through triangulation of signal strength or signal TOA from multiple Base Stations. A patient who wears the mobile device may be traveling in and out of different locations, or may stay at one location for a long period of time. Depending on the environment of the location, GPS data and Base Station distance data might not available. A more intelligent method is to detect the environment that the patient is currently in, and to adaptively assess the patient's location based on the last available GPS data and/or Base Station distance. Therefore, a preferable health monitoring system is to include an adaptive location assessment module and method, which allows a patient who wears the system to be located. This preferable health monitoring system also enables an Emergency Service Vehicle to be dispatched to the location of a patient in extreme distress or in an emergency situation.
The expansion of high speed Internet access and its comprehensive capabilities have impacted many ways of people's daily lives in recent years. The Internet and related technologies can be used in a health monitoring system to the patient's advantage. For example, in U.S. Pat. No. 6,168,563, Brown describes a system and a method that enables the health care provider to monitor and manage a health condition of a patient through a communication network such as the World Wide Web (WWW). In this invention, however, the remote health monitoring system worn by a patient is a Web-client based system, not a Web-server based system. A Web-client based health monitoring system can only respond to the request of a remote server, such as sending a patient's vital information back to the server. Such a system is operating in a passive mode and cannot react to an urgent health condition encountered by a patient in real-time when needed. One alternative to the Web-client based health monitoring system is to embed a Hypertext Transmission Protocol (HTTP) Web server in the system. In this way, a preferable health monitoring system can integrate a long-range two-way wireless communication module with a HTTP Web server. This allows the patient's family member and the medical staffs to access the system at a remote patient monitoring station using a standard Internet browser even when the patient is on the move.
A health monitoring system conducts vital sign measurements either individually or concurrently depending on system configuration. To support active, real-time monitoring functions, the system needs to decode signals from a wireless medical sensor, process measured data, and provide alter to patient if needed. In addition, the system needs to respond to external requests regarding the patient's vital signs and location. By including the capability of wireless data transmission in the system, it also needs to handle incoming and outgoing signal through a two-way wireless communication network. To provide adaptive location assessment in the system, the monitoring system also needs to retrieve and process position data from GPS satellites, and to calculate the distance from the multiple Base Station's cellular towers. Furthermore, the system needs to perform battery conservation related functions, such as putting application tasks into sleeping mode, and wake application tasks up at a pre-determined time. To administrate and manage all the above mentioned tasks simultaneously, the preferred health monitoring system should be capable of concurrent processing. In such a system, a plurality of task shared memory are created and used by all application tasks to post related task data, and receive processing instructions from an intelligent controller. An intelligent controller is responding for starting and stopping of all application tasks using the information at the task shared memory. The execution of the intelligent controller and all other application tasks are running under separate system threads concurrently to fully utilize the system's processing power.
In a mobile and wireless based health monitoring system, conserving electronically power is an important concern. The method of power conservation in such a system is to consume the least power when conducting all application tasks, and allows the system to be running for long periods of time without needing to change the power source. The preferred method of conserving power in a health monitor system is to monitor power usage through software control. In such a method, application tasks are put in sleep mode when not needed and woken up when system condition has changed or at a pre-determined time. In addition, removable and rechargeable battery is used in such a system to allow power source to be charged easily and frequently.
A need exists for a health monitoring system that uses an active, real-time monitoring method to measure and process a patient's vital signs for providing an alert on location and sending emergency requests to a remote patient monitoring station for immediate action. A need exists for a health monitoring system that contains a wireless medical sensor not only for measuring a patient's vital signs, but also for transmitting measured data to the main processing unit through short-range RF network. A need exists for a health monitoring system that incorporates the capabilities of a long-range two-way wireless communication module and a Global Position System (GPS) module along with an adaptive location assessment method for determining a patient's location. This data can then be used to transmit location information wirelessly to an Emergency Service Vehicle or a remote patient monitoring center. A need exists for a health monitoring system including a HTTP Web server that can respond to remote requests either from a patient monitoring station or from a patient's family member using a standard Internet browser, anywhere and anytime. A need exists for a health monitoring system that includes task shared memory and an intelligent controller to administrate and manage all related application tasks running concurrently under separate parallel execution threads. A need exists for a health monitoring system that uses a removable and rechargeable battery in conjunction with a software control to recharge the system and control the system's power consumption.